Functional stridor diagnosed by the anaesthetist

While stridor is an ominous sign implying severe airway stenosis, not all stridor has an organic aetiology. We present two cases of functional stridor in which the diagnosis was made by the anaesthetist. As experts in the management of difficult airways, anaesthetists should be aware of this clinical entity. Recurrent episodes present as aphonia, dysphonia, dyspnoea, apnoea or unconsciousness. Stridor is usually inspiratory. Flow volume loops show a pattern of variable extrathoracic obstruction with diminished peak inspiratory flow. Awake fibreoptic laryngobronchoscopy reveals normal airway anatomy, intense adduction of false and true vocal cords during inspiration and normal vocal cord motion on expiration. Treatment of functional stridor is supportive. The diagnosis of functional stridor demands exclusion of life-threatening airway stenosis of organic aetiology. A high index of suspicion for this clinical entity will reduce the incidence of unnecessary interventions such as tracheal intubation and tracheostomy.